Referring to FIGS. 1 and 2, a conventional electrical connector of the above-described type is shown to include a dielectric connector body 10 with a front terminal mating portion 100 for connecting with a plug (not shown). Four terminal holes 102, 102' are formed in the dielectric connector body 10 and extend from the front terminal mating portion 100 to a rear side 101 of the dielectric connector body 10. The bottom side of the connector body 10 has a rearwardly projecting tail guiding part 11 which is provided with two tail guiding slots 111. A pair of terminals 12 are respectively inserted into lower terminal holes 102 with their terminal tails 121 bent downward and passing through the tail guiding slots 111 for extension into holes of a printed circuit board. Another pair of terminals 12' which are inserted into upper terminal holes 102' also have their tails 121' passing through the tail guiding slots 111 for extension into the printed circuit board.
In the above-described electrical connector, each terminal tail 121' is longer than and extends downward behind the corresponding terminal tail 121 in the same tail guiding slot 111. Although each terminal tail 121 is guided by a portion 112 of the wall confining the corresponding tail guiding slot 111, it is not well-isolated from the adjacent terminal tail 121' since there is no positioning means in the tail guiding slot 111 for preventing the terminal tail 121' from deviating or displacing toward the terminal tail 121. Consequently, the rear terminal tails 121' are prone to deflect and touch the front terminal tails 121, thereby resulting in difficulty when fixing the terminal tails 121, 121' to the circuit board, increasing the risk of short-circuiting, and reducing the quality of transmitted signals.